Deleted 6.7 Cummins Longevity – Reliability vs Risk

Are you considering doing an EGR, DPF, or Catalytic Convertor delete on your truck but not sure about reliability or the implications it would have on your engine lifespan, reliability, warranty, or even legal issues? Interested to know if a deleted Cummins is more reliable than a well-kept stock version? If you answered yes to any of the above, then keep reading.

The benefits of a deleted 6.7 Cummins include:

  • Improved performance
  • Improved fuel economy
  • Improved reliability

We’ve all read about internet “forumites” claiming to achieve big power and reliability with deleted trucks. Many have supposedly raked up hundreds of thousands of trouble-free miles after doing a delete. Some claim to have had endless EGR problems, sluggish performance, and just an unexciting quiet driving experience prior to the delete but report the vehicle to be a completely different beast after a delete.

Sounds like a no-brainer then, and besides who would say no releasing a few extra ponies while retaining reliability right?

Not so fast!

Let’s first look at what a delete actually means and what the implications are.

What does a delete entail?

So when people talk delete, what exactly are they referring to and why is this such a popular topic? Internet forums are rife with delete threads, not only on Cummins engines but every modern diesel the world over.

So, why is this such a hot topic and why are manufactures under constant pressure to produce, safer, cleaner, greener cars? That’s because car emissions, including carbon dioxide, nitrogen oxide, and many other harmful pollutants, have negative consequences for climate change and our health. Even with all the advancements in cleaner vehicles, air pollution still remains a problem in many cities around the world. Long-term exposure to nitrogen dioxide (That’s your vehicle’s exhaust fumes) is estimated to result in 75,000 premature deaths in 40 European countries. Shocking!

So in order to please the “tree huggers” and more importantly preserve this beautiful planet as best, we can, manufactures are constantly inventing clever ways to reduce NOx emissions on modern vehicles while preserving performance and even improving on it.

Some of these emissions-reducing devices are:

  • CATS (Catalytic converters)
  • DPF (Downpipe Filters)
  • EGR (Exhaust Gas Recirculation)
  • SCR (Selective Catalytic Reduction)

A modern vehicle can be equipped with one or more of these devices, in an attempt to reduce NOx emissions. So doing a delete on your truck means removing one or all of the above-mentioned devices.

What does this mean for your vehicle?

Deleted 6.7 Cummins – Should You Do It?

So now that you know what the health and global environmental implications are, let’s investigate the warranty and legal side before we get into the “benefits” and reported reliability of doing a delete on your beloved 6.7 Cummins.

Right off the bat, ill state, yes it’s illegal to do any sort of delete on your truck. There, I said it. Also, there’s no way of completely hiding the delete from your dealership, even if the tuner replaces all the blanked-off hardware to make it appear stock to the naked, untrained eye.

Sure the dealership will need to scan specifically for evidence of the delete, in order to detect it. However, once your dealership gets wind that you’ve done any sort of emissions delete on the vehicle, your warranty comes into question immediately and might even fall away completely. It’s handled on a case-by-case basis, and some dealerships only remove the section of the warranty that directly affects the related components, while retaining the rest of the warranty. It’s all dealership-specific and, don’t quote me on that! You do these deletes at your own risk.

Now that I’m done taking the moral high ground, let’s get back to business and see what Cummins owners have to say about their deleted trucks.

What do owners say regarding deletes

I can personally say I deleted 75000 miles ago and have had zero issues. On the same hand there are guys on here with stock trucks that have 300,000 miles on them that have been trouble free. I deleted my truck to make it louder, make it sound more like a diesel, and for what I thought was a good reliability mod. That being said I just did a second gen s465 swap with valve springs, head studs, push rods, a pusher intake, Billet input shaft, Billet flexplate, triple-disc torque converter, custom-built Billet valve body, and a Billet clutch drum with all aftermarket clutches. But I also have a 68rfe. I will say this if I were to go buy a brand new truck tomorrow, I personally wouldn’t hesitate to delete it immediately again.

You can probably do nothing to it, and have no real problems for 300,000+ miles…assuming good maintenance, minimal extended idling, and complete regen cycles. I can certainly understand why you want to delete/tune…same reasons we all do. No egr/mechanical emissions, and it’s fun.

3 years and no problems. Runs great. Never to the dealer except for the tie rod inspection and even that was well within the 5 degree spec.

The only problem you are going to have if you delete is breaking something because you couldn’t keep your foot off of the loud pedal. If you are responsible and take it easy, you will not have problems. I put 40,000 miles on my ’08 6.7 deleted, 30,000 miles on a ’10 Ford PSD delted and 15,000 miles on my ’10 Dodge deleted. No problems with any of them. The only problems I had was with the ’08 before I deleted. Dodge cleaned the turbo once and then replaced it at 35,000 miles. I deleted the ’08 so I wouldn’t have to take it back to the dealer every 4-6 months with turbo issues.

Sure seems like a deleted truck is the way to go, according to these happy owners. Most report little to no issues after the delete.

Let’s now look at the benefits of a deleted truck.

Benefits of a Deleted Truck

So a deleted truck is reported to offer some of the following benefits:

  1. Improved performance
  2. They sound better
  3. Reported improved reliability
  4. Reported Improved fuel economy

Who wouldn’t want any of those benefits, right?

Manufacturers design these NOx emissions devices to not restrict and not suppress performance as much as possible. They accomplish this to a large degree while producing cleaner, greener vehicles.

The problem comes in when these devices begin to clog up over time. Nothing is designed to last forever and over a few years the honeycombs in the CATS get clogs, choking the performance, DPF’s begin to clog after years of soot build-up, even with the regular regeneration cycles. EGR systems begin to leak or fail, causing the vehicle to go into limp mode, much to the frustration of the owners.

So, it’s to be understood that more and more diesel owners are investigating removing these devices once maintenance plans and warranties have elapsed. Replacing these devices outside of warranty can run into thousands of $$$ and all with a limited lifespan. So a deleted truck simply has fewer issues that can possibly crop up.


Cummins 6.7 Diesel Filter Set (Amazon)

6.7 Cummins Diesel Fuel Water Separator (Amazon)

6.7 Cummins CAT Conversion Kit (Amazon)

6.7 Coolant Bypass Kit (Amazon)

6.7 Cummins Head Stud Replacement Kit (Amazon)


Being a performance enthusiast myself and a stickler for reliability, we do as much as we possibly can to extract the best performance out of our vehicles while maintaining reliability. Every “petrol-head“ or “diesel-head” out there is looking for that perfect balance, but unfortunately, it sometimes comes at a cost, and we live in a world governed by laws. Laws of nature, state laws, and ethical laws. Whatever makes you sleep at night!

Jade C.

4-Wheel drives and off-road driving techniques has been my passion for over 20 years. Here we strive to provide the most accurate, up-to-date, information about the functionality, common faults and latest technology built into most 4 Wheel Drives.

Recent Content